The availability of solar energy is not always coincident with the use requirements therefor in the heating of dwelling interiors and the like, and direct use of solar energy to heat air is not usually practiced since air is a light mass not conducive to the condensed storage of heat; and to these ends a heavier mass such as water has been universally employed for heat collection and storage. Solar collection involving the circulation of liquids therethrough and the voluminous storage tanks therefor are complex and expensive and entail circulation systems and special installation. The heat stored in such liquids is then transferred by suitable means and at additional expense into air for conditioning of buildings and the like, and all to the end that heating is available indirectly when desired by transfer from storage in a thermal mass. In contradistinction, the present invention involves the concept of direct air heating and heat storage in a solar collector per se, it being an object to provide solar air heating and heat storage without resorting to the previously accepted presumption that solar energy must be stored in a remote and voluminous thermal mass for subsequent use. With the present invention, solar energy is directly extracted into a useful air column or it is stored within the thermal mass of the collector structure for subsequent use.
There are useful periods of time during which the heating of air within dwellings is desired. For example, it is desirable to extend a comfortable temperature by heating a building late in the day as and when the sun passes over the horizon; and it is also desirable to establish a comfortable temperature by heating a building early in the day as the sun rises from the horizon. The former desirability requires heat energy storage for subsequent use, while the latter desirability requires immediate use of heat energy. It is an object to meet both desirabilities with the present invention which provides a thermal mass structure for retention of heat and a manifolding of said structure that provides for both direct absorption of heat into a moving column of useful air and indirect storage and subsequent transfer of heat into said air.
It is the heating of air within a structure such as a building or any chamber to be heated with which this invention is concerned, for example a room or any such chamber. It is sensible air or dry air with which this invention is primarily concerned, and air that is moderately heated on demand from a thermostat control or the like for comfort within a room to be occupied by persons, and/or air that is heated to higher temperatures as for example to be discharged through a clothes dryer or the like. In the latter instance, heated dry air discharged through damp clothes has an excellent drying effect which advantageously employs both heat and evaporation. It is an object therefore, to provide solar heated air direct from a collector for utilitarian use in comfort conditioning of building interiors and in chamber conditioning such as in the drying of clothes in a clothes drying unit.
In carrying out this invention, the solar heat collector hereinafter described is installed to face the effective sunlight, and air is blown therethrough and ducted to the utilitarian uses required. In one instance the air is blown through the solar heat collector and into the living quarters of the building on which it is installed. In another instance the air is blown through the solar heat collector and into a heat sink storage space. And in another instance the air is blown through the solar heat collector and into a clothes dryer of conventional design. It is to be understood that recirculation and discharge of the heated air column can be governed by damper controlled ducting as circumstances require.
Heretofore, the storage of heat has been related to relatively heavy masses such as water and rock etc., water having a specific heat of 1. A most widely used building material is wood, such as construction fir, having a specific heat of 0.65 and a density of about half that of water, and consequently having a "heat to volume ratio" increase of about 30% as compared with the standard "water". That is, wood actually has a heat storage capability determinable by its weight-to-volume ratio as related to its specific heat, and this capability is considerable and establishes wood as an efficient thermal mass. In this respect, therefore, it is an object of this invention to employ wood as a heat sink or thermal mass for the storage of solar heat, and simultaneously as the structure of the solar heat collector in which it is employed as the structure elements thereof.